On June 2, the Environmental Protection Agency unveiled new sulfur dioxide (SO2) primary national ambient air quality standards (NAAQS). The EPA’s main reason for revoking the former standards is the public health risk posed by sulfur oxides, which SO2 is a part. They claim that sulfur oxides react with compounds in the atmosphere to form particulates that pose health risks to intensify existing heart conditions or may cause and worsen certain respiratory conditions. EPA estimates show the cost of the new ruling will be approximately $1.5 billion; however, it estimates the health benefits between $13 and $33 billion. Power generation sites and cement plants will be particularly affected by the EPA’s new ruling. These plants are known for temporary SO2 spikes, especially during the start-up and shutdown of combustion equipment.
The particulars of the regulation require that plants maintain a level of no more than 75 parts per billion (ppb) of SO2 evaluated over a one hour period compared with the former rule of 140 ppb evaluated over a twenty-four hour period. This new ruling also overturns the other standard of maintaining a level of no more than 30 ppb evaluated over a year. The second part of the new regulation also revises the ambient air monitoring system. The EPA feels that 41 new monitoring stations will need to be established for operation beginning the first of January, 2013. These new sites will use air quality modeling and air dispersion monitoring to designate the areas that meet or fail the new standards, designated “attainment” and “non-attainment” areas. All sites must meet the new standards no later than August 2017. Secondary SO2 standards will be addressed in a separate ruling.
One immediate effect of this action is that Prevention of Significant Deterioration (PSD) permits issued after the effective date of the new NAAQS must include a compliance demonstration with respect to the new NAAQS.